1. Field of the Invention
The present invention relates to a projection system, and more particularly, to a LCOS panel assembly of a projection system that can provide a high definition screen for long time by a LCOS panel assembly in a reflecting-type projection system in which an image is formed by a LCOS Panel.
Still more particularly, it relates to a LCOS panel assembly of a projection system and an image matching method of the LCOS panel assembly which can provide a high definition screen even though the projection system is continuously used for long time, as foreign substance is prevented from being injected into the inside of the LCOS panel assembly and after a lot of parts constituting the LCOS panel assembly are coupled to each other, deformation due to residual stress between coupled portions is prevented, and image matching between parts provided at the inside of the LCOS panel assembly is reliably performed to prevent deformation between parts when using a product.
2. Description of the Background Art
Unlike a general liquid crystal display, a liquid crystal on silicon (hereinafter, referred to as “LCOS”) that is a kind of a reflecting-type liquid crystal display forms a liquid crystal cell on a semiconductor substrate and can realize a high definition of a XGA grade or more in a small size of about one inch by arranging switching circuits and elements of each pixel in high integration.
For these reasons, the LCOS panel has been attracted as a display device of the projection system and technical development and commercialization of the LCOS panel and a projection display system using the LCOS panel have been actively progressed.
In order to embody a full color screen, the LCOS projection system uses a three panel type which converts white color light to RGB three color light, has three LCOS panels corresponding to the R, G, B light to compose R, G, B images embodied by each LCOS panel in a color image, and projects the composed image to a screen.
Such general LCOS projection system includes an illumination unit for projecting light, a composition unit for composing RGB three images displayed in the LCOS panel in an image after projecting light, a projecting lens for projecting light composed in the composition unit, and a screen for displaying light projected from the projecting lens to an image.
Specifically, three LCOS panels are additionally fixed to the composition unit, after each of RGB three color light separated from white color light is incident to the LCOS panel, it is reflected and the reflected light is composed. A quarter-wave plate is provided in a neighboring position of the LCOS panel to improve a contrast of an image. The quarter-wave plate performs an operation converting linear polarized light to circular polarized light.
On the other hand, because a contrast of an image is deteriorated and a color of an image is inaccurately expressed when matching of the quarter-wave plate and the LCOS panel is not perfectly performed, it is general to perform again matching of the quarter-wave plate and the LCOS panel while actually watching an image after the projection system is manufactured.
However, when manufacturing of the projection system is completed, it is not easy to control the quarter-wave plate.
Further, when the quarter-wave plate is manufactured in a movable type, foreign substance may be injected into a space between the quarter-wave plate and the LCOS panel. If foreign substance is attached on the quarter-wave plate, light transmitting a place where foreign substance is attached is intercepted, whereby a desirable image is not formed. For example, if foreign substance is attached on a red color LCOS panel, red color light is not reflected in the LCOS panel, whereby a pixel to be displayed in white color is displayed in cyan color that is the sum of green color and blue color with red color subtracted. Because foreign substance may be injected into other parts in addition to the quarter-wave plate and the LCOS panel at the inside of the LCOS panel, it is an important in the LCOS panel assembly to provide a perfect sealing structure so that foreign substance can not be injected into a space between all parts constituting the LCOS panel.
Further, as described above, because the LCOS panel assembly is manufactured by coupling of a lot of parts, a lot of coupled portions are generated, and because residual stress remaining in the coupled parts causes continuous deformation even after manufacturing of the projection system is completed, there is a problem that matching is not made. If image matching is not made in the LCOS panel assembly, it is difficult to embody a desired pixel, whereby deterioration of an image is generated.